The invention relates to a system for supervision and control of objects or persons within a limited area, such as a building, comprising a plurality of electronic identification chips for placing on respective objects/persons to be supervised/controlled, each chip having stored a special ID code and being provided with a transmitter and a receiver for communication via ultrasound, a plurality of stationary detectors interconnected in a network and arranged for both-way communication with the chips, and a central control unit communicating with the chips via the detectors.
There is previously known a system of the above-mentioned type which is constructed for localizing persons by means of individual badges or marker chips, and wherein the system is based on signalling by means of ultrasound. In this known system the badges have an ultrasonic signature which is extractable by means of special ultrasonic sensors mounted in walls or ceilings in e.g. a building, and wherein the sensors constitute a transceiver which is able to transmit and receive an ultrasonic signal over a distance range of up to 10 m. The system comprises a control unit communicating with the badges via said sensors. When a badge is situated in the communication region of a sensor, the control unit stores the identification number of the badge, the identification of the sensor encountering the badge, and date and time for the coincidence. This information is transmitted in coded form by means of ultrasound to a central control unit in the form of e.g. a computer or PC.
A substantial weakness of the previously known system is that signalling with ultrasound is dependent on a free visibility between the marked object and the current sensor or detector, or a high degree of saturation of the localization area with ultrasound from a large number of transmitters. In order to remedy this weakness, some systems have added signalling by means of radio signals. However, this creates problems for electronically sensitive equipment.
The above-mentioned known system neither can be used in another important field of application, viz. with active supervision and control of objects, persons etc. within a complex of buildings, a building or parts of a building. Such supervision and control is of substantial importance within many fields of the society. As examples there may be mentioned hospitals and other health institutions, insurance companies, factories, laboratories, air ports, banks, military installations, guard companies, hotels, offices, shops, dwellings, etc.
A problem or a weakness with the known systems for access and movement control, is that they are switched off when authorized personnel is within the supervised or controlled area. This implies that also other persons can get into and/or move freely within the same area without an alarm being triggered. Thus, within the same system, there is not distinguished between access control and the number of persons that can move (authorized or non-authorized movements) after having passed the access control. This means reduced security and reduced survey/control. The same otherwise applies to private dwellings where unauthorized persons seek entry with the intention of profit while persons are present, because a possible alarm then is switched off.
Another weakness of the existing systems is the lacking safety of authorized personnel. As a consequence of the fact that the alarms in most cases are switched off after adequate admission through coded, electronic or other control systems, unauthorized persons canxe2x80x94when the alarm is switched offxe2x80x94easily move within such areas if they have obtained access to forbidden zones. Dangerous situations and unsafe working places thereby arise, especially in the evening and at night. There are many examples of personnel in such situations having been assaulted by thieves or drug addicts in desperate pursuit of narcotics, cf. hospitals. Especially, existing systems manage badly in large institutions having a large personnel traffic, such as applies to hospitals, military quarters, banks, etc. Especially the unsafety of the personnel increases from daytime to afternoon, evening and night.
An additional weakness or drawback of the existing systems is that they only to a small extent allow differentiation of the alarm generation in the effected access/movement control. For example, traffic in a hospital corridor or a transport conduit will be able to give alarm with any movement, or no alarm at all when access authorization has been obtained.
In active supervision and control of objects it is often also important to be able to provide for routine maintenance of equipment which has to be taken in for control and testing after given time periods. In some cases it is also the total operating time of the equipment which is the criterion for calling in for control and testing.
There exist data systems with software which takes care of routine maintenance of said type. The location of the equipment of interest then is generally recorded in a central computer. The drawback of these known systems is that they do not automatically manage to locate equipment which is moved, and that they therefore require use of time and resources from personnel to recover such mobile equipment or tools. Equipment which is only to be used a given number of operating hours, will also require much resource use and severe demands on human routines in that personnel physically must check and keep control over the operating time. Common to the known systems is that they are based on a great administrative work with the effort of considerable labour, careful and accurate registrations of equipment and operating time, and running maintenance programs. These operations have in common that a great discipline from many people is required, something which often fails and involves a need for a great effort of labour. Seeking is perceived as unnecessary trouble and delay, and therefore results. in a poorer working environment and a great turnover of personnel.
On this background it is an object of the invention to provide a flexible and programmable system which provides for access and movement control of persons, objects and documents within a complex of buildings, a building or parts of a building, at the same time as the above-mentioned weaknesses/drawbacks are avoided, so that authorized personnel can move freely within the topical area while an alarm will be given if unauthorized persons get into the same area.
The above-mentioned object is achieved with a system of the introductorily stated type which, according to the invention, is characterized in that each chip and each detector also is provided with a transmitter and a receiver for communication via audible sound (audio), a means being provided for switching between ultrasonic and audio communication, and that each chip in operation is continuously active and is arranged to transmit its ID code at predetermined time intervals, the detector or the control unit being arranged to trigger an alarm unit if an incorrect code is received or an approved code is not received continuously at chosen time intervals.
In the system according to the invention authorized personnel is equipped with an active ID chip with both-way wireless ultrasonic and audio communication and having a special ID code for the person carrying the chip. In case of entry into an area requiring authorization, the system will recognize the chip and fail to give an alarm. This takes place in that the chip at a preprogrammed time interval gives a coded message to detectors placed around in relevant areas that it is present and is authorized. The detectors, which may either be a separate self-contained unit or a subcomponent in a superior central system, will verify the ID code emitted by the chip. Chips emitting codes which are not in accordance with allowed codes, will cause activation of the alarm system, locally or centrally. This takes place in that a number of stationary detectors, which are interconnected in a network and are arranged for both-way communication with the chips, and a main central or subcentral communicating with the chips via the sensors/detectors and possible repeaters, will activate the alarm system. Similarly, unauthorized persons without such chips will do the same in that they enter into zones covered by detectors. These detectors are constructed for reacting both to ultrasonic and audio signalling and also to movement within their area. The principle of detection of movement may be both infrared radiation (IR) and ultrasound, or other known principles.
A further object of the invention is to provide a system providing for calling and localization of objects and equipment, for example in connection with automatic call-in to routine or operational maintenance of equipment which must be brought in for control and testing after given time periods.
This object is achieved with a system of the introductorily stated type which, according to the invention, is characterized in that each chip and each detector also is provided with a transmitter and a receiver for communication via audible sound (audio), a means being provided for switching between ultrasonic and audio communication, and that the central control unit is arranged to selectively call a chosen chip via the detectors, and that the chips are arranged to give an answer as a reaction to the call, the closest situated detector then identifying the site/locality of the chip.
In the above stated system the central control unit will, in case of a requirement for routine maintenance of equipment, automatically give a message to the detectors which in turn will call the relevant marker or ID chip. The chip will respond, and the detector which is closest, will give a message, and since a detector is stationary, the location is defined within the communication distance between the chip and the detector. The chips also have the possibility to activate themselves after a preprogrammed time interval. If some equipment has a requirement for test and control after a certain number of hours of operation, the chip may contain inputs registering the length of active operating time having elapsed at any time, and give a return message to the central control unit. The advantage which is achieved, is that one has an automatic system which does not need to pay regard to human routines in that personnel physically must check and keep control over the operating time and the errors which may normally arise in this connection. Further, the system is very resource-saving in that all the time one has control from a central location of where equipment is located, and then especially portable/movable equipment.
A substantial advantage of the system according to the invention is that it does not xe2x80x9ccontaminatexe2x80x9d the environment within the range of application of the system with electromagnetic fields which may disturb electromagnetically sensitive equipment. This is of substantial importance, for example in a hospital environment.
A field of application wherein the system according to the invention will be very advantageous, is in retrieval of journals (patient journals) and equipment in hospitals. In this connection the combination of sound and ultrasound will increase the detection from about 60% when using only ultrasound to 100% with sound. The combination is both important and advantageous, as audio communication is introduced only when one does not find xe2x80x9cthe target objectxe2x80x9d with detection of ultrasound alone. Thereby on avoids xe2x80x9ccontaminationxe2x80x9d of the environment to a too great extent. Possibly one may also use audio communication in an updating of the location of all the topical objects (patient journals) at certain times of the day, for example evening and/or morning.
Thus, the system provides a safe retrieval of journals and equipment, provided the relevant rooms have got a detector installed. This means that it is not necessary to have free lines of sight to the objects of interest, or to saturate large areas with ultrasound by means of many wave generators. Ultrasound is easily stopped by physical obstacles, such as paper. Safe detection therefore would require a system which could also pick up ultrasonic waves reflected from walls, objects, etc., something which is technically difficult and would result in a more expensive solution. This is the reason why the problem with retrieval of journals and equipment in confined rooms has not previously been solved in a satisfactory manner. As mentioned above, some systems have added RF communication. However, the limitation to rooms then will not be sufficiently accurate without the help of large number of aerials, and at the same time one gets undesired electromagnetic fields.
The system according to the invention also provides automated maintenance routines with indication of the place where the equipment is located, something which gives large possibilities for rationalization profits in relation to the systems of today, especially when it is the question of portable or movable equipment.